1. Field of the Invention
The present invention relates to a novel machine (the Compressed Air Turbine-Generator, or CAT-G) to manage energy gathered from renewable sources, such as solar and wind power. Compressed Air Energy Storage (C.A.E.S.) is a promising mode of clean energy storage. A major challenge facing this technology is the need to efficiently convert the compressed air energy into electricity. Commonly, the high-pressure air is used only to improve the efficiency of a conventional jet-powered turbine generator. The focus herein is on a new technology that efficiently converts the energy stored in compressed air directly into electrical power without producing greenhouse byproduct gases or other pollutants. This new capability will add important flexibility to the optimization of ecologically friendly energy systems.
2. Background Discussion
A common deficiency of many Renewable Energy schemes is the lack of an effective way to store the energy for use when the source is not operational. Wind and solar power provide such challenges. FIG. 1 shows a practical system that is based on the compression of air and the storage of energy (in a “Heat” and a “Pressure” Reservoir) at ambient atmospheric temperature, TO. It illustrates that wind power can be used to compress air (from the atmosphere) so that high pressure air goes into a ‘C.A.E.S. Energy Storage Reservoir’ and the energy from the constant temperature (Isothermal) air compression flows (as heat) into a Water (Heat) Reservoir. (Heating the water in this tank does raise its temperature slightly so that, in general, TWATER≧TO; but this elevation in temperature is not critical to the storage-recovery process).
An obvious advantage of this configuration is that the energy stored at TO is not lost by dissipation to the environment. Any energy reservoir that is hotter than TO must lose energy to colder regions by convection, conduction and radiation. With the energy reservoirs held at, or near TO, thermal convection, conduction and solar heating helps stabilize the energy reservoirs, as energy (via heat-flow) is consumed in the recovery part of the storage-recovery process.
It is also apparent that a vital element of this scheme is a means for recovering the stored energy from the reservoirs and delivering it in a useful form. Although the focus herein is on the design and operation of the CAT-G, it is important to remember that the behavior of the energy reservoirs (including the Earth's atmosphere) at T≈TO must be understood as critical parts of the storage and recovery system.